<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>Three.js - Scenegraph - Sun Earth</title>
    <style>
    html, body {
        height: 100%;
        margin: 0;
        color: white;
        font-family: monospace;
    }
    #c {
        width: 100%;
        height: 100%;
        display: block;
    }
    #ui {
        position: absolute;
        right: 1em;
        top: 1em;
        background: rgba(64, 64, 64, 0.8);
        padding: .5em;
    }
    #ui .axisgrid {
        display: flex;
        align-items: center;
    }
    #ui .axisgrid:nth-child(odd) {
      background: rgba(72, 72, 72, 0.8);
    }
    #ui .label {
        width: 8em;
        overflow: hidden;
        text-overflow: ellipsis;
    }
    #ui .checkbox {
        display: flex;
        align-items: center;
    }
    </style>
  </head>
  <body>
    <canvas id="c"></canvas>
    <div id="ui"></div>
  </body>
<script type="importmap">
{
  "imports": {
    "three": "../../build/three.module.js",
    "three/addons/": "../../examples/jsm/"
  }
}
</script>

<script type="module">
import * as THREE from 'three';
import { GUI } from 'three/addons/libs/lil-gui.module.min.js';

function main() {

	const canvas = document.querySelector( '#c' );
	const renderer = new THREE.WebGLRenderer( { antialias: true, canvas } );
	const gui = new GUI();

	const fov = 40;
	const aspect = 2; // the canvas default
	const near = 0.1;
	const far = 1000;
	const camera = new THREE.PerspectiveCamera( fov, aspect, near, far );
	camera.position.set( 0, 50, 0 );
	camera.up.set( 0, 0, 1 );
	camera.lookAt( 0, 0, 0 );

	const scene = new THREE.Scene();

	{

		const color = 0xFFFFFF;
		const intensity = 3;
		const light = new THREE.PointLight( color, intensity );
		scene.add( light );

	}

	const objects = [];

	const radius = 1;
	const widthSegments = 6;
	const heightSegments = 6;
	const sphereGeometry = new THREE.SphereGeometry(
		radius, widthSegments, heightSegments );

	const solarSystem = new THREE.Object3D();
	scene.add( solarSystem );
	objects.push( solarSystem );

	const sunMaterial = new THREE.MeshPhongMaterial( { emissive: 0xFFFF00 } );
	const sunMesh = new THREE.Mesh( sphereGeometry, sunMaterial );
	sunMesh.scale.set( 5, 5, 5 );
	solarSystem.add( sunMesh );
	objects.push( sunMesh );

	const earthOrbit = new THREE.Object3D();
	earthOrbit.position.x = 10;
	solarSystem.add( earthOrbit );
	objects.push( earthOrbit );

	const earthMaterial = new THREE.MeshPhongMaterial( { color: 0x2233FF, emissive: 0x112244 } );
	const earthMesh = new THREE.Mesh( sphereGeometry, earthMaterial );
	earthOrbit.add( earthMesh );
	objects.push( earthMesh );

	const moonOrbit = new THREE.Object3D();
	moonOrbit.position.x = 2;
	earthOrbit.add( moonOrbit );

	const moonMaterial = new THREE.MeshPhongMaterial( { color: 0x888888, emissive: 0x222222 } );
	const moonMesh = new THREE.Mesh( sphereGeometry, moonMaterial );
	moonMesh.scale.set( .5, .5, .5 );
	moonOrbit.add( moonMesh );
	objects.push( moonMesh );

	// Turns both axes and grid visible on/off
	// GUI requires a property that returns a bool
	// to decide to make a checkbox so we make a setter
	// can getter for `visible` which we can tell GUI
	// to look at.
	class AxisGridHelper {

		constructor( node, units = 10 ) {

			const axes = new THREE.AxesHelper();
			axes.material.depthTest = false;
			axes.renderOrder = 2; // after the grid
			node.add( axes );

			const grid = new THREE.GridHelper( units, units );
			grid.material.depthTest = false;
			grid.renderOrder = 1;
			node.add( grid );

			this.grid = grid;
			this.axes = axes;
			this.visible = false;

		}
		get visible() {

			return this._visible;

		}
		set visible( v ) {

			this._visible = v;
			this.grid.visible = v;
			this.axes.visible = v;

		}

	}

	function makeAxisGrid( node, label, units ) {

		const helper = new AxisGridHelper( node, units );
		gui.add( helper, 'visible' ).name( label );

	}

	makeAxisGrid( solarSystem, 'solarSystem', 26 );
	makeAxisGrid( sunMesh, 'sunMesh' );
	makeAxisGrid( earthOrbit, 'earthOrbit' );
	makeAxisGrid( earthMesh, 'earthMesh' );
	makeAxisGrid( moonOrbit, 'moonOrbit' );
	makeAxisGrid( moonMesh, 'moonMesh' );

	function resizeRendererToDisplaySize( renderer ) {

		const canvas = renderer.domElement;
		const width = canvas.clientWidth;
		const height = canvas.clientHeight;
		const needResize = canvas.width !== width || canvas.height !== height;
		if ( needResize ) {

			renderer.setSize( width, height, false );

		}

		return needResize;

	}

	function render( time ) {

		time *= 0.001;

		if ( resizeRendererToDisplaySize( renderer ) ) {

			const canvas = renderer.domElement;
			camera.aspect = canvas.clientWidth / canvas.clientHeight;
			camera.updateProjectionMatrix();

		}

		objects.forEach( ( obj ) => {

			obj.rotation.y = time;

		} );

		renderer.render( scene, camera );

		requestAnimationFrame( render );

	}

	requestAnimationFrame( render );

}

main();
</script>
</html>
